Additively Manufactured Pressurization Diffusers

ABSTRACT

Example implementations relate to Additive Manufacturing (AM) pressurization diffusers. An example diffuser includes an integral component configurable for receiving and diffusing pressurant. Particularly, the integral component includes multiple elements manufactured as a single-piece structure, including an inner filter, outer shell, and flange. The inner filter includes micro-diamond holes that enable pressurant received at an opening of the inner filter to diffuse out of the inner filter and subsequently through holes positioned in a shell surface of the outer shell. The flange can position the diffuser such that the opening of the inner filter is in pressurant communication with a pressurant source (e.g., opening of a tank) enabling the diffuser to receive and diffuse pressurant in a predefined pattern. For example, when the diffuser is positioned inside a tank, the diffuser can have a frustum configuration that helps diffuse pressurant upwards towards inner sidewalls of a pressure vessel, tube or channel.

CROSS-REFERENCE TO RELATED APPLICATION

The present patent application is a continuation of U.S. patentapplication Ser. No. 15/640,217, filed on Jun. 30, 2017, the entirecontents of which are hereby incorporated by reference.

STATEMENT OF GOVERNMENT INTEREST

This invention was made with Government support under HR0011-14-9-0005awarded by Defense Advanced Research Projects Agency. The government hascertain rights in this invention.

FIELD

The present disclosure relates generally to tank pressurizationdiffusers and hydraulic components, and more particularly to AdditiveManufactured (AM) tank pressurization diffusers configurable forreceiving and diffusing pressurant within a pressurant tank or othertype of apparatus.

BACKGROUND

Propellant tanks are pressure vessels configured to store pressurant,such as liquid fuel, liquid oxidizer, or other chemical substances usedto propel a vehicle. For example, rockets and aircrafts may rely uponstored pressurant to generate propulsive thrust to enable flight.Efficient use of pressurant is important for various reasons, includingthe cost and weight associated with the pressurant. Therefore, measuresare often taken to improve pressurant expulsion efficiency.

One measure aimed to improve pressurant delivery involves using a tankpressurization diffuser that can reduce undesirable mixing of tankullage gas or vapor with the liquid pressurant in a tank. In particular,a diffuser can be configured to passively introduce a pressurizing gasor vapor (also simply referred to as pressurant) directly into the upperregion of a liquid propellant tank in such a manner as to reduce thevelocity of the vapor or gas to prevent inadvertent mixing with theliquid pressurant already stored within the tank. The diffuser can bedesigned with the goal of limiting or eliminating direct impingement ofthe pressurant with the liquid propellant to decrease the heat transferbetween the pressurant and liquid surface to ensure optimum expulsionand pressurization efficiency.

Existing diffusers are historically assembled from multiple components,such as screens or perforated components including machined parts thatare attached together via mechanical fasteners (e.g., screws, bolts, andrivets) or by brazing or welding. The multiple component configurationof the diffuser, however, can result in vibrational, fatigue, and otheroperational problems that could impact performance. Themultiple-component configuration also requires individuallymanufacturing each component prior to assembly which consumes additionaltouch labor time and adds additional expense. Furthermore, since theparts must be assembled together using simple shapes (flat surfaces forexample), the complexity of the diffuser's design is often limited bytraditional manufacturing processes, which can then limit thecapabilities and performance of the diffuser. Thus, there is a need fora non-conventional diffuser design and manufacturing process that iscapable of receiving and passively (in traditional use) redirectingpressurant in a manner that effectively reduces unwanted mixing ofpressurant within a tank while also avoiding the limitations oftraditional, multiple-component diffusers.

SUMMARY

In one example, an apparatus is described comprising an integralcomponent configurable for receiving and diffusing pressurant. Theintegral component includes an outer shell having a shell surfacepositioned between a first end and a second end. In some instances, theshell surface includes a first plurality of holes. The integralcomponent also includes an inner filter positioned inside the outershell. Particularly, a first end of the inner filter extends through anopening in the first end of the outer shell and includes an opening forreceiving pressurant. In addition, a second end of the inner filter iscoupled to the second end of the outer shell. As such, the inner filterincludes a second plurality of holes positioned between the first endand the second end of the inner filter such that pressurant received viathe opening at the first end of the inner filter diffuses through thesecond plurality of holes and subsequently through the first pluralityof holes in the shell surface of the outer shell. The integral componentalso includes a flange coupled to the first end of the inner filter.Particularly, the flange is configurable for coupling the apparatus suchthat the opening at the first end of the inner filter is in pressurantcommunication with a pressurant source.

In another example, a tank is described comprising an integral componentextending toward a center of the tank from an inner surface of the tank.The integral component is configurable for receiving and diffusingpressurant. Particularly, the integral component includes an outer shellhaving a shell surface positioned between a first end and a second end.The shell surface includes a first plurality of holes. The integralcomponent also includes an inner filter positioned inside the outershell. A first end of the inner filter extends through an opening in thefirst end of the outer shell and includes an opening that is inpressurant communication with an opening of the tank. A second end ofthe inner filter is coupled to the second end of the outer shell. Theinner filter includes a second plurality of holes positioned between thefirst end and the second end such that pressurant received via theopening at the first end of the inner filter diffuses through the secondplurality of holes and subsequently through the first plurality of holesin the shell surface of the outer shell.

In another example, a method is described. The method includes receivingpressurant at an inner filter of an integral component. Particularly,the pressurant is received via an opening at a first end of the innerfilter, and the integral component is configurable for receiving anddiffusing the pressurant and includes an outer shell positioned aroundthe inner filter. The outer shell includes a shell surface having afirst plurality of holes positioned between a first end and a second endof the outer shell. The method also includes diffusing the pressurantreceived at the opening at the first end of the inner filter from theintegral component. In particular, diffusing the pressurant from theintegral component involves initially diffusing the pressurant from theinner filter through a second plurality of holes positioned in the innerfilter between the first end and a second end of the inner filter, andsubsequently diffusing the pressurant through the first plurality ofholes in the shell surface of the outer shell.

The features, functions, and advantages that have been discussed can beachieved independently in various examples or may be combined in yetother examples further details of which can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE FIGURES

The novel features believed characteristic of the illustrative examplesare set forth in the appended claims. The illustrative examples,however, as well as a preferred mode of use, further objectives anddescriptions thereof, will best be understood by reference to thefollowing detailed description of an illustrative example of the presentdisclosure when read in conjunction with the accompanying drawings,wherein:

FIG. 1 is an illustration of an apparatus, according to an exampleimplementation.

FIG. 2 is a cross-sectional illustration of the apparatus, according toan example implementation.

FIG. 3 is another illustration of the apparatus, according to an exampleimplementation.

FIG. 4 is an additional illustration of the apparatus, according to anexample implementation.

FIG. 5 is an illustration of the flange of the apparatus, according toan example implementation.

FIG. 6 is another illustration of the flange of the apparatus, accordingto an example implementation.

FIG. 7 is an illustration of a tank configured with an integralcomponent, according to an example implementation.

FIG. 8 shows a flowchart of an example method of passively receiving anddiffusing pressurant.

FIG. 9 shows a flowchart of an example method for use with the methodshown in FIG. 8, according to an example implementation.

DETAILED DESCRIPTION

Disclosed examples will now be described more fully hereinafter withreference to the accompanying drawings, in which some, but not all ofthe disclosed examples are shown. Indeed, several different examples maybe described and should not be construed as limited to the examples setforth herein. Rather, these examples are described so that thisdisclosure will be thorough and complete and will fully convey the scopeof the disclosure to those skilled in the art.

Example implementations relate to pressurization diffusers capable ofreceiving and diffusing pressurant in a predefined pattern.Particularly, some examples involve additively manufactured diffusersthat are designed and created in a manner that all elements of adiffuser are intraconnected as a single-piece structure withoutrequiring any assembly. Unlike existing diffusers assembled usingmultiple components, an additively manufactured diffuser is createdusing a layer-upon-layer generation process that enables the variouselements of the diffuser to be generated together as an integralcomponent.

Similar to a multiple-component diffuser, the Additively Manufactured(AM) diffuser can passively receive and diffuse pressurant in apredefined pattern. For example, an additively manufactured diffuser canbe positioned inside a tank near the opening of the tank such that theincoming pressurant received at the tank is passively redirected by thediffuser away from the liquid propellant surface of the tank.Redirection of the incoming pressurant helps prevent the pressurant fromdirectly impinging and chaotically mixing with other liquid propellantalready positioned within the tank. In particular, the diffuser can bedesigned to reduce the associated velocity and heat transfer of theincoming pressurant enabling the pressurant to gently settle into theother contents (e.g., propellant) occupying the tank. As a result, thediffuser can help improve the use and expulsion efficiency of thepressurant.

In addition, the single-piece intraconnected structure of an additivelymanufactured diffuser can perform more effectively thanmultiple-component diffusers. Particularly, the intraconnected structurereduces vibration and fatigue issues that often impact the performanceof multiple-component diffusers, as well as enables fine-tuning ofstructural geometry or tailoring of resonant modal frequencies. Further,Additive Manufacturing (AM) also allows a diffuser to have a complexdesign with design aspects that can improve performance since thelayer-upon-layer generation process eliminates the need to independentlymanufacture components that must be assembled together.

Referring now to the Figures, FIG. 1 is an illustration of an apparatus100, according to an example implementation. The apparatus 100 is anexample diffuser that includes an integral component 102 configurablefor receiving and diffusing pressurant. As shown in FIG. 1, the integralcomponent 102 consists of intraconnected elements making up theapparatus 100, including an outer shell 104, an inner filter 114, and aflange 122. Additional configurations are described below.

The apparatus 100 can passively redirect pressurant by adjusting theentry flow pattern of the pressurant. In some example applications, theapparatus 100 is positioned within a tank nearby the opening of the tankto enable the apparatus 100 to passively receive and redirect incomingpressurant away from the liquid propellant surface and perhaps towardone or more inner sidewalls of the tank. The passive redirection of thepressurant away from the liquid surface and perhaps towards innersidewalls of the tank helps prevent the pressurant from forcefullymixing with liquid propellant already occupying the tank. As a result,the apparatus 100 can improve expulsion efficiency and use of thepressurant.

Unlike diffusers assembled from multiple components, the apparatus 100involves multiple elements intraconnected as a single-piece structure.Particularly, Additive Manufacturing (AM) enables the apparatus 100 andother physical objects to be created as intraconnected single-piecestructure through the use of a layer-upon-layer generation process.Additive Manufacturing (AM) involves depositing a physical object in oneor more selected materials based on a design of the object. For example,Additive Manufacturing (AM) can generate the apparatus 100 using aComputer Aided Design (CAD) of the apparatus 100 as instructions. As aresult, changes to the design of the apparatus 100 can be immediatelycarried out in subsequent physical creations of the apparatus 100. Thisenables the apparatus 100 to be easily adjusted or scaled to fitdifferent types of applications (e.g., for use in various tank sizes).

The layer-upon-layer process utilized in Additive Manufacturing (AM)enables the creation of the apparatus 100 to have all elements (e.g.,the inner filter 114, the outer shell 104, the flange 122)intraconnected to form the integral component 102. As a result, theapparatus 100 does not require screws, bolts, or other types offasteners to connect and stabilize elements, and thus does not includeany unwanted gaps or diversity of tolerances that can occur betweenconnections. Rather, the single-piece structure of the apparatus 100 canperform passive pressurant redirection without subjecting the apparatus100 to vibrational and fatigue issues that often impactmultiple-component diffusers.

Additionally, the layer-upon-layer generation process also can depositthe apparatus 100 with complex designs that might not be possible fordiffusers assembled with multiple components. In turn, the design of theapparatus 100 can include aspects that aim to improve overall operation.For example, the design can incorporate physical elements that helpredirect incoming pressurant in a desired manner that multiple-componentdiffusers might not be able to replicate.

Additive Manufacturing (AM) also enables depositing the apparatus 100 ina variety of materials. For instance, in some examples, the apparatus100 is deposited using nickel-chromium-based super alloys (e.g., Inconel625 for ductility in cryogenic environments and durability inhigh-temperature environments) or other materials that are resistant tocorrosions. Inconel 625 comprises nickel and resists oxidation, remainsductile at cryogenic temperatures, and remains strong at hightemperatures. As such, Inconel 625 is a viable option for the apparatus100 to enable the apparatus 100 to maintain strength after numeroususes. In other examples, other materials are used.

In another example implementation, the apparatus 100 is generated usinga combination of different materials. The apparatus 100 can have somelayers that are created using a first type of material and other layersthat are created using a second type of material. In addition, variousprocesses are used in other examples to produce the apparatus 100. Theseprocesses are included in table 1.

TABLE 1 DEP Direct Energy Deposition DMLS Direct Metal Laser SinteringDMP Direct Metal Printing EBAM Electron Beam Additive Manufacturing EBMElectron Beam Leting EBPD Electron Beam Powder Bed FDM Fused DepositionModeling IPD Indirect Power Bed LCT Laser Cladding Technology LDT LaserDeposition Technology LDW Laser Deposition Welding LDWM Laser DepositionWelding with integrated Milling LENS Laser Engineering Net Shape LFMTLaser Freeform Manufacturing Technology LMD-p Laser MetalDeposition-powder LMD-w Laser Metal Deposition-wire LPB Laser Powder BedLPD Laser Puddle Deposition LRT Laser Repair Technology PDED PowderDirected Energy Deposition SLA Stereolithography SLM Selective LaserMelting SLS Selective Laser Sintering SPD Small Puddle Deposition

In some example implementations, the apparatus 100 is generated usingmelt-away support materials, such as sulfone, thermoplastic, polyester,organic composite photoresist materials and dry film resists.Particularly, during the layer-upon-layer generation process, amelt-away support material can support elements of the apparatus 100until the apparatus 100 is complete and stable enough to standalone. Inturn, the melt-away support material can support physical aspects of theapparatus 100 during the layer-upon-layer generation process until theapparatus 100 is completed. After the apparatus 100 is completed, themelt-away support material can be removed to leave only the apparatus100 remaining. For instance, a water soluble melt-away support materialcan rinse away from portions of the apparatus 100.

In an example implementation, the apparatus 100 is constructed using oneor more elastic materials. Elastic materials can enable the apparatus100 to be compressed and expanded during operation. Quasi-elasticmaterials can similarly be used to create the apparatus 100. Forexample, when the apparatus 100 is deposited using quasi-elasticmaterials, the apparatus 100 can be stowed in a low-volume configurationand subsequently expanded for use. As such, the apparatus 100 may beconfigured for uses beyond passive flow control, including deployment ofdiffuser for use and/or deformation of diffuser during use, as neededfor myriad functional needs, gradients of flow rates, or variousenvironmental conditions in various regimes during the operationenvelope of flight.

The integral component 102 of the apparatus 100 includes intraconnectedelements enabling the integral component 102 to receive and diffusepressurant in a predefined manner. The different elements areintraconnected as a single-piece structure.

The outer shell 104 of the integral component 102 is configured with ashell surface 106 positioned between a first end 108 and a second end110. The first end 108 and the second end 110 are shown with circularconfigurations, but can have other suitable configurations (e.g.,octagonal, hexagonal, pentagonal, rectangular, triangular, or the like).Additionally, in some examples, the shape of the first end 108 candiffer from the shape of the second end 110 (e.g., the first end 108 iscircular and the second end 110 is octagonal). In some examples, bothends may have the same shape with the same major and minor diameters.

As shown in the illustration of FIG. 1, the first end 108 of the outershell 104 has a greater circumference than the second end 110 of theouter shell 104. The size difference results in the outer shell 104forming a frustum configuration that can help direct the flow ofpressurant, and therefore heat, dispersed from the apparatus 100 upwardsin a direction out and/or away from the second end 110. The frustumdesign of the outer shell 104 helps direct pressurant in an upwardmanner away from the liquid propellant surface. In other examples, theouter shell 104 can have other configurations designed to direct flow ofpressurant as desired. For instance, the outer shell 104 can have a bellpepper or cylindrical configuration in example implementations.

Additionally, in the example implementation, a portion of the first end108 of the outer shell 104 curves inward towards the second end 110 ofthe outer shell 104. Similarly, the second end 110 of the outer shell104 includes a portion that curves inwards towards the first end 108 ofthe outer shell 104. The curvature in the first end 108 and the secondend 110 can help direct diffused pressurant as desired. In otherexamples, the first end 108 and the second end 110 can have more or lesscurvature. For instance, one or both of the first end 108 and the secondend 110 can have a flat design. In instances where melt-away material isnot used, the second end 110 can exhibit sloped ceilings away from bothinner and outer shells to enable layer-by-layer deposition without useof break-away supports, as such supports might be trapped in theinternal volume.

Within examples, adjusting the parameters of the first end 108 and thesecond end 110 can modify the outer shell 104 to alter the output of theapparatus 100. For instance, the perimeters of the first end 108 and thesecond end 110 can vary in size, thickness, or other parameters withinexamples. For example, in another example implementation, the first end108 of the outer shell 104 can have a first shape configuration and thesecond end 110 can have a second shape configuration that differs fromthe configuration of the first end 108. As such, the perimeters of thefirst end 108 and the second 110 can also differ or equal in size toadjust the configuration of the shell surface 106.

Additionally, the thickness of the shell surface 106 can also varywithin example implementations. For instance, the shell surface 106 canhave a uniform thickness in some examples. In other examples, portionsof the shell surface 106 can vary in thickness. For example, an upperportion of the shell surface 106 located near the first end 108 of theouter shell 104 can have a different thickness than a portion of theshell surface 106 located near the second end 110 of the outer shell104. The variations in the thickness of the shell surface 106 can impactthe flow pattern for diffusing incoming pressurant.

In some implementations, the outer shell 104 can include one or morelips, plates, scales, flaps, or other structural aspects to assist indirecting pressurant leaving the apparatus 100. For example, the outershell 104 can include one or more flaps that help direct the pressurantaway from the liquid propellant towards inner sidewalls of a tank. Insome instances, the physical aspects added to the outer shell 104 needto adhere to build limitations associated with Additive Manufacturing(AM) (e.g., a 37-53 degree build limitation).

In some examples, the second end 110 of the outer shell 104 can includea lip that extends around a perimeter of the second end 110. The lip cancause pressurant diffused from the inner filter 114 to diffuse radiallyoutward and at an upward angle generally toward the first end 108 and/oraway from the send end 110, from the integral component 102.

Flaps, lips, and other physical aspects, however, can have otherconfigurations when melt-away support material is used to support thedesign of the apparatus 100 during the Additive Manufacturing (AM)process. For example, scales or other structural aspects of the outershell 104 can have bends, kinks, or other modifications to set theaspects into desired positions. For example, scales positioned on theouter shell 104 can include scalloped trailing edges similar to theconfiguration of edges on a fir cone from the Douglas-Fir.

As shown in FIG. 1, the shell surface 106 of the outer shell 104includes a first plurality of holes 112 that enable pressurant receivedto disperse from the apparatus 100. In particular, the positions andconfigurations of the holes 112 can impact the redirection pattern forpressurant diffusing from the apparatus 100. As such, in some examples,the positions and configurations of the holes 112 in the shell surface106 are optimized based on the sub-sonic and sonic orificecross-sectional areas that exist between the outer shell 104 and theinner filter 114 and within the inner filter 114, respectively. As anexample, the size of each hole in either shell may be determined bysizing the total cross-sectional feed-through area, based on fluid-flowequations, and then dividing by the quantity of holes, noting that somemanufacturing restrictions may limit the quantity of holes (e.g.,minimum wall-thickness and minimum hole size).

The sonic orifices are used to choke the pressurant at the design flowrate at given inlet pressure and temperature conditions. The Sonic flowequation provides the flow rate given the total summation of the chokedeffective area also known as C_(d)A. The subsonic orifices on the outershell are used to further diffuse the pressurant velocity to subsonicvelocities while entering the propellant tank. Reducing the velocity tosubsonic conditions help reduce the heat transfer between the pressurantand liquid surface thereby increasing propellant expulsion efficiency.

In some examples, the holes 112 in the shell surface 106 can each beshaped in a diamond configuration. The diamond configuration enablesdepositing the holes 112 using Additive Manufacturing (AM) while alsoenabling the outer shell 104 to maintain structural strength. In someconfigurations, the diamond-shaped holes 112 can include filletedcorners to mitigate stress-fracture promulgation as a product ofstress-focusing.

In other examples, the holes 112 in the shell surface 106 can have othershapes, such as a teardrop configuration or hexagonal configuration. Forexample, the holes 112 can have a micro-nozzle configuration,converging-diverging, diverging, and/or converging shape that cancompress or expand pressurant as the pressurant diffuses (or effuses)through.

In some examples, the shell surface 106 can have multiple-shaped holes112. For instance, a first set of the holes 112 in the shell surface 106can have a first configuration (e.g., diamond) and a second set of theholes 112 can have a second configuration (e.g., teardrop). In addition,the holes 112 can be arranged in a uniform or non-uniform mannerdepending on desired flow paths for dispersed pressurant. For example,the shell surface 106 can involve a mosaic of diamond, hexagonal,parallelogram, trapezoidal, trapezium, and/or other shaped holes 112with some portions of the shell surface 106 lacking holes as well. Insome implementations, the entire outer shell 104 may be solid with onlyone exit hole, flange, or spigot, such that the apparatus 100 can serveas a filter.

The holes 112 in the shell surface 106 of the outer shell 104 can alsobe sized based on the sub-sonic flow equation shown in equation [1]. Inequation [1], P₁ represents the pressure between the inner filter 114and the outer shell 104, and P₂ represents the pressure that exists justoutside the holes 112 in the shell surface 106 of the outer shell 104.

$\begin{matrix}{\overset{.}{m} = {P_{o}{AM}\sqrt{\frac{2g_{c}\gamma}{\left( {\gamma - 1} \right){RT}}\left\lbrack {\left( \frac{P_{2}}{P_{1}} \right)^{\frac{2}{\gamma}} - \left( \frac{P_{2}}{P_{1}} \right)^{\frac{\gamma + 1}{\gamma}}} \right\rbrack}}} & \lbrack 1\rbrack\end{matrix}$

In equation [1], {dot over (m)} is the mass flow rate, P_(o) is theupstream total pressure, A is the area, M is Mach number, g_(c) is theacceleration of gravity, y is the specific heat ratio, R is the gasconstant, T is the temperature, P₁ is the pressure between the innercylinder and the outer shell, and P₂ is the pressure just outside thediamond-pattern holes of the outer shell.

The integral component 102 also includes an inner filter 114 positionedinside the outer shell 104. The inner filter 114 is the element of theapparatus 100 that is positioned to initially receive and diffuseincoming pressurant. Particularly, a first end 116 of the inner filter114 extends through an opening 115 in the first end 108 of the outershell 104 and includes an opening 119 for receiving the incomingpressurant.

As such, the inner filter 114 includes a second plurality of holes 120positioned between the first end 116 and a second end 118, which mayalso include a variety or mosaic of shapes from diamond to hexagonal toteardrop, etc. In some example implementations, the second plurality ofholes 120 are positioned between the first end 108 of the outer shell104 and the second end 118 of the inner filter 114.

The holes 120 in the inner filter 114 allow pressurant received at theopening 119 in the first end 116 to diffuse out from the inner filter114 into the area positioned between the inner filter 114 and the outershell 104. Particularly, in some implementations, the area between theinner filter 114 and the outer shell 104 can differ depending on thedesired flow pattern for dispersing pressurant from the apparatus 100.For instance, in some examples, the distance between the inner filter114 and the outer shell 104 is based on a desired mass flow rate for theintegral component 102. The volume that exists between the inner filter114 and the outer shell 104 may depend on the total surface area of theshell surface 106. The volume can also depend on geometrically tuningthe diffuser so as to avoid sensitive, resonant frequency mods. Thevolume may also be tailored so as to increase or decrease mixing betweenshells.

As shown in FIG. 1, the second end 118 of the inner filter 114 iscoupled to the second end 110 of the outer shell 104. Particularly, thesecond end 110 of the outer shell 104 encloses the second end 118 of theinner filter 114 to prevent pressurant from flowing out at the secondend 118 of the inner filter 114. As a result, the inner filter 114 andother elements of the apparatus 100 can redirect the flow of pressurantaway from the liquid propellant and towards inner sidewalls or theceiling of the tank via the shape and position of elements of theapparatus 100. In some examples, the second end 118 of the inner filter114 is enclosed during the Additive Manufacturing (AM) layer-upon-layergeneration process.

In some examples, the length between the first end 116 and the secondend 118 of the inner filter 114 is selected based on a desired mass flowrate for the inner filter 114. The desired mass flow rate represents themass of pressurant that flows through holes 120 in the inner filter 114per unit of time. When the inner filter 114 is longer, and/or hasgreater cross-sectional area, more pressurant can flow through the holes120 to disperse from the inner filter 114. The thickness of portions ofthe inner filter 114 as well as other parameters (e.g., sizes of theholes 120) can alter the dispersion of pressurant from the inner filter114 as well as from the apparatus 100 overall.

Further, in some examples, the orifice area of the inner filter 114 isdesigned for choked flow equations such that equation [2] applies. Forexample, in some cases, the cross-sectional area of the inner filter 114is based on desired choked flow conditions for the integral component102.

$\begin{matrix}{\overset{.}{m} = {C_{D}{AP}_{o}\sqrt{\frac{g}{zRT}{\gamma \left( \frac{2}{\gamma + 1} \right)}^{\frac{\gamma + 1}{\gamma - 1}}}}} & \lbrack 2\rbrack\end{matrix}$

In equation [2], C_(D) is the discharge coefficient, z is thecompressibility factor and all other variables are described above withregards to equation [1].

Choked flow is a fluid dynamic condition associated with thecompressible gas dynamics. Particularly, when pressurant at a givenpressure and temperature passes through a restriction (e.g., the holesin the inner filter 114) into a lower pressure environment, the velocityof the pressurant decreases. At initially subsonic upstream conditions,the conservation of mass principle requires the pressurant velocity toincrease as it flows through the smaller cross-sectional area of theholes 120 in the inner filter 114. The venturi effect causes the staticpressure and density to wane downstream beyond the holes 120 in theinner filter 114. Choked flow represents a limiting condition where themass flow of the pressurant will not increase with a further wane in thedownstream pressure environment while upstream pressure is fixed.

The mass flow rate is approximated for LO2 wherein equation [3] applies.

$\begin{matrix}{{\overset{.}{m}}_{O\; 2} = \frac{0.559C_{D}{AP}_{o}}{\sqrt{T_{O}}}} & \lbrack 3\rbrack\end{matrix}$

The mass flow rate is approximated for LH2 as shown in equation [4].

$\begin{matrix}{{\overset{.}{m}}_{H\; 2} = \frac{0.14C_{D}{AP}_{o}}{\sqrt{T_{O}}}} & \lbrack 4\rbrack\end{matrix}$

In equation [4], m is the mass flow rate, C_(D) is the dischargecoefficient, A is the area, P_(o) is the upstream total pressure. Thecompressible flow equation may be re-expressed in terms of Mach numberat the diffuser inlet as shown in equation [5].

$\begin{matrix}{\overset{.}{m} = {P_{o}{AM}\sqrt{\frac{\gamma \; g_{c}}{{RT}_{o}}}\frac{1}{\left( {1 + {\frac{\gamma - 1}{2}M^{2}}} \right)^{(\frac{\gamma + 1}{2{({\gamma - 1})}})}}}} & \lbrack 5\rbrack\end{matrix}$

As indicated above, the inner filter 114 includes the holes 120 thatenable pressurant received via the opening 119 at the first end 116 ofthe inner filter 114 to diffuse out of the inner filter 114 andsubsequently through the holes 112 in the shell surface 106 of the outershell 104. As such, the position and configuration of holes 120 in theinner filter 114 can vary within examples. As shown, the holes 120 inthe inner filter 114 have pin-shapes (or rather, small diamond-shapes).In some implementations, the holes 112 in the shell surface 106 of theouter shell 104 are larger than the respective holes 120 in the innerfilter 114.

In a further example implementation, the inner filter 114 can bemanufactured without other elements of the apparatus 100. As astandalone structure, the inner filter 114 can be used in otherapplications, such as a hydraulic filter. Other applications for the AMfilter beyond aerospace can include a sieve and/or a colander.

The integral component 102 also includes a flange 122 coupled to thefirst end of the inner filter 114. The flange 122 is configurable forcoupling the apparatus such that the opening 119 at the first end 116 ofthe inner filter 114 is in pressurant communication with a pressurantsource (e.g., gas source). For instance, in some examples, the flange122 connects the apparatus 100 near the curved dome of a tank such thatthe apparatus 100 can disperse pressurant away from the propellantliquid surface out towards the sidewalls of the tank.

Within examples, parameters of the flange 122 can vary. For instance, inan example implementation, the flange 122 has a sinusoidal configurationor rectangular configuration. In addition, the flange 122 is furthershown with a groove 123 configured with a circular shape, but can haveother configurations (e.g., octagonal, pentagonal, etc.). The groove 123can enable a seal to be placed in the flange 122 to prevent unwantedleakage and can house an o-ring. In some examples, the flange 122 caninclude multiple grooves 123.

FIG. 2 is a cross-sectional view of the apparatus 100, according to anexample implementation. The cross-sectional view of the apparatus 100depicts the interiors of elements of the integral component 102,including interior views of the inner filter 114 and outer shell 104.The cross-sectional view of the apparatus 100 shows the variousconnections between the elements of the apparatus 100 that is possiblethrough the use of Additive Manufacturing (AM).

The inner filter 114 is shown as intraconnected to the flange 122 andthe outer shell 104 of the apparatus 100. In particular, the first end116 of the inner filter 114 is deposited as connected to the flange 122with the opening 119 of the inner filter 114 formed into a centerportion of the flange 122. This configuration enables pressurant todirectly enter into the inner filter 114 via the opening 119 sans anygaps between the flange 122 and the inner filter 114 to potentiallyleak.

In addition, the inner filter 114 is shown as intraconnected at thefirst end 108 and the second end 110 of the outer shell 104. As shown inFIG. 2, a portion of the inner filter 114 is connected to the first end108 of the outer shell 104 at the opening 115 of the first end 108 andthe second end 118 of the inner filter 114 is intraconnected with thesecond end 110 of the outer shell 104. The second end 118 of the innerfilter 114 has a pointed, cone-like, closed-end configuration thatextends as an intraconnected peak into the second end 110 of the outershell 104. As such, a groove 121 in the second end 110 of the outershell 104 and the peak formed at the second end 118 of the inner filter114 can assist in directing pressurant out of the holes 120 in the innerfilter 114 at an upward angle radially outward from the apparatus 100.

In some examples, the second end 110 of the outer shell 104 and thesecond 118 of the inner filter 114 can form discontinuous angledsurfaces, such as a conic surface angled away from the first end 108 ofthe outer shell 104 with the groove 121 in the second end 110 extendingaround the conic surface. The discontinuous angled surfaces formed bythe second end 110 and the second end 118 can further include aninverted conic surface that is angled back towards the first end of theouter shell 104, and a conic surface that encloses the second end 118 ofthe inner filter 114. The different conic surfaces formed by the secondend 110 and the second end 118 can direct pressurant flow upward andaway from liquid propellant positioned within a tank.

FIG. 3 is another illustration of the apparatus 100, according to anexample implementation. In particular, the integral component 102 of theapparatus 100 is shown as having a seal 124 coupled to the flange 122.The seal 124 is positioned within a groove extending into anoutward/mating face of the flange 122 (e.g., a face of the flange 122).The flange face is configurable to mate with the tank such that the seal124 extends around a perimeter of the flange and prevents receivedpressurant from leaking out of the opening 119 at the first end 116 ofthe inner filter 114. The seal 124 can also prevent fluid from enteringinto a tank via the opening of the tank. The size and configuration ofthe seal 124 can vary within examples. For instance, the seal 124 canhave a pentagonal shape that includes four faces and an opening.

In addition, FIG. 3 further shows a foundation portion of the apparatus100 formed by the second end 118 of the inner filter 114 and the secondend 110 of the outer shell 104 can have a configuration that assists indirecting pressurant diffused from the apparatus 100. In particular, thesecond end 118 of the inner filter 114 extends into an angled grooveformed in the second end 110 of the outer shell 104 such that the angledgroove closes the second end 118 of the inner filter 114 and preventsreceived pressurant from leaking out of the inner filter 114 at thesecond end 110 of the inner filter 114. As such, the second end 118 ofthe inner filter 114 is generated as a portion of the second end 110 ofthe outer shell 104 using a layer-upon-layer generation process.

The configuration formed in the foundation portion of the apparatus 100can help direct pressurant diffused from the inner filter 114 and outthe holes 112 of the outer shell 104 upward from the apparatus 100.Particularly, the angled groove formed in the second end 110 of theouter shell 104 can enable pressurant diffused through the holes 120 inthe inner filter 104 to flow radially out and upward toward the firstend 108 of the outer shell 104. The second end 110 of the outer shell104 and the second end 118 of the inner filter 114 combine to form acontinuous enclosure surface for the apparatus 100, preventingpressurant from flowing out of the end of apparatus 100 opposite firstend 108.

In some examples, the second end 118 of the inner filter 114 isgenerated as a portion of the second end 110 of the outer shell 104using the layer-upon-layer generation process of Additive Manufacturing(AM). This configuration differs from the foundation portions ofdiffusers made out of multiple components because the inner filter andthe foundation portion of the outer shell of multiple-componentdiffusers are typically separate components fastened together, which canresult in a diversity of tolerances and, therefore, an imperfect union.

FIG. 4 is an additional illustration of the apparatus 100, according toan example implementation. The apparatus 100 is shown coupled to anotherapparatus and includes the integral component 102 involving variouselements intraconnected as a single-piece structure. Particularly, theintegral component 102 includes the outer shell 104 configured with theshell surface 106 positioned between the first end 108 and the secondend 110. The shell surface 106 of the outer shell 104 includes holes 112that are each shaped in a diamond configuration. The holes 112 arearranged in a radial, extrude-cut pattern across the shell surface 105,but can have non-uniform layouts within other example implementations.

The integral component 102 further includes the inner filter 114positioned inside the outer shell 104 such that pressurant can diffusefrom the pin-shaped, parallelogram-shaped, trapezoidal-shaped,trapezium-shaped, or micro-diamond shaped holes 120 extending along theinner filter 114 and subsequently through the holes 112 in the shellsurface 106 of the outer shell 104. The inner filter 114 includes thefirst end 116 extending through the opening 115 in the first end 108 ofthe outer shell 104. The first end 116 of the inner filter 114 alsoforms a connection with the flange 122 and includes the opening 119 forreceiving pressurant for the apparatus 100 to passively diffuse thepressurant, and heat, in a desired pattern (e.g., towards one or moreinner sidewalls of a tank). The inner filter 114 also includes thesecond end 118 intraconnected with the second end 110 of the outer shell104 as aforementioned.

The second end 110 of the outer shell 104 is further shown with a tip125. The tip 125 can be used to mount an accelerometer or other sensingequipment (e.g., heater, cooler, laser source) to test the performanceof the apparatus 100. The performance test can enable further designchanges in subsequent production of the apparatus 100. The tip 125 canalso provide a flat face for insertion of diagnostic equipment or asurface for machining a hole to further manipulate performance of theapparatus 100. The tip 125 may include a diamond-shaped pilot hole. Thetip 125 may be manufactured during the build or after the build on anyflat or non-flat surface.

The flange 122 of the integral component 102 includes slots that enablethe apparatus 100 to be coupled to another apparatus via use offasteners (i.e., screws). In other examples, Additive Manufacturing (AM)can enable the flange 122 to be deposited as a portion of the otherapparatus (e.g., an extension within a tank) such that the apparatus 100and the other apparatus form a single-piece structure without requiringany assembly.

FIG. 5 is an illustration of the flange 122 of the apparatus 100,according to an example implementation. The flange 122 is shown with aGibbous O-ring Layering (GOL) or snapping o-ring land 126 configured asa pentagonal shape that can avoid a vertical overhang. For example, theangle of the sloped roof can be 53-55 degrees from the horizon, which iswithin range of the Additive Manufacturing (AM) depositional limits. Insome instances, the snapping o-ring land 126 further incorporatesfillets to eliminate stress-fracture promulgation. In some cases, thereare also fillets at the clamping edges to mitigate wear on the snappingo-ring land 126.

FIG. 6 is another illustration of the flange 122 of the apparatus 100,according to an example implementation. The Gibbous O-ring Layering(GOL) 127 can be embedded in implementations with use of pentagonalshaping. As discussed above, the Gibbous O-ring Layering 127 is oneexample of geometry for securing an o-ring on any AM sealing surfacewhich may disengage.

FIG. 7 is a conceptual illustration of a tank 130, according to anexample implementation. The tank 130 includes an integral component 132extending toward a center of the tank 130 from an inner surface 134 ofthe tank 130. Additional configurations are possible.

The integral component 132 is shown as a part of the tank 130.Particularly, Additive Manufacturing (AM) or a similar process cangenerate the tank to include the integral component 132 in asingle-piece intraconnected structure. For example, AdditiveManufacturing (AM) can deposit the tank 130 using a blend of aluminumlithium powder. Similar to the integral component 102 of FIGS. 1-2, theintegral component 132 is configurable for passively receiving anddiffusing pressurant towards one or more inner surfaces 136 (e.g.,sidewalls, ceiling) of the tank.

As shown in FIG. 7, the integral component 132 includes an outer shell138 configured with a shell surface 140 positioned between a first end142 and a second end 144. The second end 144 of the outer shell 138 hasa smaller diameter than the diameter of the first end 142 of the outershell 138 causing the outer shell 138 to have a frustum configuration.In other examples, however, the outer shell 138 can have otherconfigurations, such as a bell pepper, complex curves, or cylindricalshape (using “cylindrical” in both layman's terms or the mathematicallexicon). The shell surface 140 can include a first plurality of holes146 with the holes 146 having diamond configurations.

In other implementations, the holes 146 can have other shapes andlayouts in the shell surface 140. For example, one or more portions ofthe shell surface 140 can lack holes 146 such that the integralcomponent 132 diffuses pressurant in a desired manner.

Positioned inside the outer shell 138 is an inner filter 148 thatoperates similarly to the inner filter 114 described above. Inner filteris generally co-axial with the outer shell. In other examples, the twostructures are not co-axial, and in others, only portions are co-axial.The first end 150 of the inner filter 148 extends through an opening 154in the first end 142 of the outer shell 138 and includes an opening 152that is in pressurant communication with an opening of the tank 130. Theinner filter 148 also includes a second end 156 that is coupled to thesecond end 144 of the outer shell 138. In particular, the second end 156of the inner filter 148 is shown as a closed end such that pressurantcannot diffuse directly through the second end 156.

The inner filter 148 includes a second plurality of holes 158 positionedbetween the first end 150 and the second end 156 of the inner filter 148such that pressurant received via the opening 152 at the first end 150of the inner filter 148 diffuses through the second plurality of holes158. After diffusing through the holes 158 in the inner filter 148, thepressurant can further diffuse through the holes 146 in the shellsurface 140 of the outer shell 138 in a manner that directs thepressurant away from the liquid propellant surface towards innersidewalls walls of the tank 130. This configuration enables the integralcomponent 132 to diffuse pressurant away from the liquid propellantsurface upward towards the first end 142 of the outer shell 138 andradially outward toward the sides of the tank to mitigate chaotic mixingof the pressurant with propellant(s) already positioned within the tank130. As such, the integral component 132, including the size and shapeof elements, positions of holes in the shell surface 140 and innerfilter, and other parameters can alter the dispersion paths ofpressurant from the integral component 132 into the tank 130.

FIG. 8 shows a flowchart of an exemplary method of receiving anddiffusing pressurant within a pressurant tank, according to an exampleimplementation. Method 160 shown in FIG. 8 presents an example of amethod that could be used with the apparatus 100 shown in FIGS. 1-6 orthe tank shown in FIG. 7. In other examples, components of the devicesand/or systems may be arranged to be adapted to, capable of, or suitedfor performing the functions, when operated in a specific manner.

Method 160 may include one or more operations, functions, or actions asillustrated by one or more of blocks 162 and 164. Although the blocksare illustrated in a sequential order, these blocks may also beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

At block 162, the method 160 involves receiving pressurant at an innerfilter of an integral component. The pressurant is received via anopening at a first end of the inner filter. As such, the integralcomponent is configurable for receiving and diffusing the pressurant,and includes an outer shell positioned around the inner filter.Particularly, the outer shell includes a shell surface configured with afirst plurality of holes positioned between a first end and a second endof the outer shell.

At block 164, the method 160 involves diffusing the pressurant receivedat the opening at the first end of the inner filter from the integralcomponent. In particular, diffusing the pressurant from the integralcomponent includes initially diffusing the pressurant from the innerfilter through a second plurality of holes positioned in the innerfilter between the first end and a second end of the inner filter, andsubsequently diffusing the pressurant through the first plurality ofholes in the shell surface of the outer shell.

FIG. 9 shows a flowchart of an example method for use with the method160, according to an example implementation. At block 166, functionsinclude causing the diffused pressurant to further diffuse outward at anupward angle from the integral component. For instance, causing thediffused pressurant to further diffuse outward at the upward angle fromthe integral component can involve using one or more of a lip extendingaround a perimeter of the second end of the outer shell, a conic surfaceangled away from the first end of outer shell formed by the second endof the inner filter and the second end of the outer shell, and a frustumconfiguration formed by the outer shell.

By the term “substantially” or “about” used herein, it is meant that therecited characteristic, parameter, or value need not be achievedexactly, but that deviations or variations, including for example,measurement error, measurement accuracy limitations and other factorsknown to a person having ordinary skill in the art, may occur in amountsthat do not preclude and/or occlude the effect the characteristic wasintended to provide.

The description of the different advantageous arrangements has beenpresented for the purposes of illustration and description, and is notintended to be exhaustive or limited to the examples in the disclosedform. Many modifications and variations will be apparent to those ofordinary skill in the art. Further, different advantageous examples maydescribe different advantages as compared to other advantageousexamples. The example or examples selected are chosen and described inorder to best explain the principles of the examples, the practicalapplication, and to enable others of ordinary skill in the art tounderstand the disclosure for various examples with variousmodifications as are suited to the particular use contemplated.

What is claimed is:
 1. A method comprising: receiving pressurant at aninner filter of an integral component, wherein the pressurant isreceived via an opening at a first end of the inner filter, wherein theintegral component is configurable for receiving and diffusing thepressurant and includes an outer shell positioned around the innerfilter, and wherein the outer shell includes a shell surface having afirst plurality of holes positioned between a first end and a second endof the outer shell; and diffusing the pressurant received at the openingat the first end of the inner filter from the integral component,wherein diffusing the pressurant from the integral component comprises:initially diffusing the pressurant from the inner filter through asecond plurality of holes positioned in the inner filter between thefirst end and a second end of the inner filter; and subsequentlydiffusing the pressurant through the first plurality of holes in theshell surface of the outer shell.
 2. The method of claim 1, furthercomprising: causing the pressurant to further diffuse outward at anupward angle from the integral component.
 3. The method of claim 2,wherein causing the pressurant to further diffuse outward at the upwardangle from the integral component involves using one or more of a lipextending around a perimeter of the second end of the outer shell, aconic surface angled away from the first end of the outer shell formedby the second end of the inner filter and the second end of the outershell, and a frustum configuration formed by the outer shell.
 4. Themethod of claim 1, wherein the first end of the outer shell has agreater circumference than the second end of the outer shell such thatthe outer shell has a frustum configuration.
 5. The method of claim 1,wherein one or more portions of the shell surface of the outer shelllacks respective holes of the first plurality of holes.
 6. The method ofclaim 1, wherein respective holes in the first plurality of holes in theshell surface of the outer shell are larger than respective holes in thesecond plurality of holes in the inner filter.
 7. The method of claim 1,wherein one or more holes in the first plurality of holes in the shellsurface of the outer shell has a diamond configuration.
 8. The method ofclaim 1, wherein one or more holes in the first plurality of holes inthe shell surface of the outer shell has a teardrop configuration. 9.The method of claim 1, wherein the integral component further comprises:a flange coupled to the first end of the inner filter, wherein theflange is configurable for coupling the integral component such that theopening at the first end of the inner filter is in pressurantcommunication with a pressurant source.
 10. The method of claim 1,wherein the second end of the inner filter extends into an angled grooveformed in the second end of the outer shell such that the angled groovecloses the second end of the inner filter and prevents receivedpressurant from leaking out of the inner filter at the second end of theinner filter.
 11. A method comprising: generating, using alayer-upon-layer generation process, an integral component configurablefor receiving and diffusing pressurant, wherein the integral componentcomprises: an outer shell having a shell surface positioned between afirst end and a second end, wherein the shell surface includes a firstplurality of holes; an inner filter positioned inside the outer shell,wherein a first end of the inner filter extends through an opening inthe first end of the outer shell and includes an opening for receivingpressurant, wherein a second end of the inner filter is coupled to thesecond end of the outer shell, and wherein the inner filter includes asecond plurality of holes positioned between the first end and thesecond end of the inner filter such that pressurant received via theopening at the first end of the inner filter diffuses through the secondplurality of holes and subsequently through the first plurality of holesin the shell surface of the outer shell; and a flange coupled to thefirst end of the inner filter, wherein the flange is configurable forcoupling the integral component such that the opening at the first endof the inner filter is in pressurant communication with a pressurantsource.
 12. The method of claim 11, wherein generating the integralcomponent further comprises: generating the integral component such thata cross-sectional area of the inner filter is based on preventing chokedflow conditions for the integral component.
 13. The method of claim 11,wherein generating the integral component further comprises: generatingthe integral component such that a distance between the inner filter andthe outer shell is based on a desired mass flow rate for the integralcomponent.
 14. The method of claim 11, wherein generating the integralcomponent further comprises: generating the integral component such thata length between the first end of the inner filter and the second end ofthe inner filter is based on a desired mass flow rate for the integralcomponent.
 15. The method of claim 11, wherein generating the integralcomponent further comprises: generating the integral component using anickel-chromium-based super alloy.
 16. The method of claim 11, whereingenerating the integral component further comprises: generating theintegral component with one or more fasteners for coupling the integralcomponent inside a tank such that the pressurant received via theopening at the first end of the inner filter that diffuses through thesecond plurality of holes and subsequently through the first pluralityof holes in the shell surface of the outer shell and further diffusesaway from a liquid propellant surface toward one or more inner walls ofthe tank proximate the opening of the tank.
 17. The method of claim 11,wherein generating the integral component further comprises: generatingthe integral component such that the first end of the outer shell has agreater circumference than the second end of the outer shell such thatthe outer shell has a frustum configuration.
 18. The method of claim 11,wherein generating the integral component further comprises: generatingthe integral component such that respective holes in the first pluralityof holes in the shell surface of the outer shell are larger thanrespective holes in the second plurality of holes in the inner filter.19. The method of claim 11, wherein generating the integral componentfurther comprises: generating the integral component such thatrespective holes in the first plurality of holes in the shell surface ofthe outer shell are larger than respective holes in the second pluralityof holes in the inner filter.
 20. The method of claim 11, whereingenerating the integral component further comprises: generating theintegral component such that the second end of the inner filter extendsinto an angled groove formed in the second end of the outer shell suchthat the angled groove closes the second end of the inner filter andprevents received pressurant from leaking out of the inner filter at thesecond end of the inner filter.